territorial island; island belonging to a country
Refers to an island that is politically and administratively part of a larger country, often used in geographical or geopolitical contexts.
Okinotorishima is a territorial island of Japan.
Compound of 属 (zoku, 'belonging to') + 島 (tō, 'island'). The exact historical derivation is uncertain, but the term is a straightforward Sino-Japanese compound.